Whistle tone in Tentdac

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#6
Is the whistle tone audible at both channels
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Yes the tone is in both channels.
I made a mistake with T=1.5 µSec, time base was set to x2.
T is 3 µSec.
The volume of the tone changes regulary and is lower when set to PAUZE and STOP. Loudest when playing music. I use the pcm1704 adapter, but changing this for a pcm1702 adapter from Linn has the same result.
I'll try to observe the results so I can give more to the point data.
Any recommandation what I have to test?
Kind regards.
JP
 
#9
Report: (att Guido and Peranders and others)

1 The tone comes from the RADIO input of my Quad 44 and not from the DAC. My mistake, I used Radio and not the CD input.
Maybe oscillation? All is n ormal with the tuner as source on this input.

2 The signal on the regulator U23 is a mystery for me. Can this affect the sound quality of the DAC?

3 The noise level on the direct output after the filter is about 8 mV pp. Measured with an old oscilloscope. Mostly hum and noise.
Is this value good? The noise is good detectable when playing loud and then the CD player set to PAUSE.

Help is welcome.
JP
 
#10
jpfastre said:
Report: (att Guido and Peranders and others)

1 The tone comes from the RADIO input of my Quad 44 and not from the DAC. My mistake, I used Radio and not the CD input.
Maybe oscillation? All is n ormal with the tuner as source on this input.

2 The signal on the regulator U23 is a mystery for me. Can this affect the sound quality of the DAC?

3 The noise level on the direct output after the filter is about 8 mV pp. Measured with an old oscilloscope. Mostly hum and noise.
Is this value good? The noise is good detectable when playing loud and then the CD player set to PAUSE.

Help is welcome.
JP
Click to expand...

Hi JP

2: I have no DAC available here curently, so cannot verify, but will do once my own DAC i back

best
 
#14
Here some results of my tests:

I played a CDR which sounded horrible on my DAC. The normal analog output of my QUAD (the first Quad CD player 66 with CDM4 drive) was much better but the distortion was also present. It sounds like mistracking (cracks, grainy noise and with the DAC is also a modulated noise present but much louder than with the normal output)

It is not possible to make a copy of this CDR with NERO (sync error)

My questions are:

1. Is the error correction of the normal player before or after the SPDIF output?
2. Why is the DAC not so tolerant as the CD player?
3. Anyone with the same trouble?
4. Hints to resolve this issue.

BTW the sound of a good CD is very good with this DAC!

JP
 
#15
jpfastre said:
Here some results of my tests:

I played a CDR which sounded horrible on my DAC. The normal analog output of my QUAD (the first Quad CD player 66 with CDM4 drive) was much better but the distortion was also present. It sounds like mistracking (cracks, grainy noise and with the DAC is also a modulated noise present but much louder than with the normal output)

It is not possible to make a copy of this CDR with NERO (sync error)

My questions are:

1. Is the error correction of the normal player before or after the SPDIF output?
2. Why is the DAC not so tolerant as the CD player?
3. Anyone with the same trouble?
4. Hints to resolve this issue.

BTW the sound of a good CD is very good with this DAC!

JP
Click to expand...

1.) Error correction is done in the digital processor before spdif output.
2.) Because DAC unit is faulty.
3.) No but I had a cd player with crackling/rustling noise at the output of one channel.

4.) The problem in #3.) was solved by replacing the DAC.It could also be the opamp but I doubt it.

Goodluck.
 
#16
jpfastre said:
Here some results of my tests:

I played a CDR which sounded horrible on my DAC. The normal analog output of my QUAD (the first Quad CD player 66 with CDM4 drive) was much better but the distortion was also present. It sounds like mistracking (cracks, grainy noise and with the DAC is also a modulated noise present but much louder than with the normal output)

It is not possible to make a copy of this CDR with NERO (sync error)

My questions are:

1. Is the error correction of the normal player before or after the SPDIF output?
2. Why is the DAC not so tolerant as the CD player?
3. Anyone with the same trouble?
4. Hints to resolve this issue.

BTW the sound of a good CD is very good with this DAC!

JP
Click to expand...

Hi Jean Pierre

I am not sure what is going on, but there may be an error in your DAC. I invite you to the lab in Eindhoven so we can have a look at it and cary out some measurements.

best
 
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